ELASTICS CHARACTERISTICS OF CONCRETES BY DYNAMIC METHODS

A RESEARCH WORK PERFORMED AT THE CONCRETE LABORATORY, TECHNOLOGY DIVISION, OF THE GUANABARA STATE HIGHWAY DEPARTMENT IN RIO DE JANEIRO, DURING THE YEARS OF 1962 TO 1965 IS PRESENTED. THE ELASTIC CHARACTERISTICS OF CONCRETES USED IN SEVERAL PROJECTS OF THIS STATE WERE STUDIED BY MEANS OF RESONANT FREQUENCY, ACCORDING TO TEST METHODS ASTM C 215/60 AND JIS A 1127/58 (JAPAN), AND USING THE FORMULAE OF THE MATHEMATICAL THEORY OF ELASTICITY. ABOUT 2000 TESTS WERE PERFORMED ON CYLINDRICAL SPECIMENS (15 X 30CM) OF CONCRETE USED IN PAVEMENTS AND BRIDGE STRUCTURES. THE PORTLAND CEMENT USED IN THESE CONCRETE MIXES WAS THE TYPE I, ASTM C 150-63. AFTER RUNNING THE SONIC TESTING SPECIMENS WERE SUBMITTED TO COMPRESSIVE STRENGTH TESTS. THE PRINCIPAL RESULT OF THIS RESEARCH WAS THE ESTABLISHMENT OF EXPERIMENTAL FORMULAE RELATING THE MODULUS OF ELASTICITY TO THE COMPRESSIVE STRENGTH. THE PAPER PRESENTS THE BASIC FORMULAE FROM THE THEORY OF ELASTICITY, AND DESCRIBES EQUIPMENT AND TEST METHODS. THE FINAL REMARKS CAN BE SUMMARIZED AS FOLLOWS: (1) WHEN STUDYING THE CORRELATION OF THE DYNAMIC MODULUS OF ELASTICITY WITH THE COMPRESSIVE STRENGTH, ONE SHOULD GROUP EXPERIMENTAL DATA ACCORDING TO AGE OF CONCRETES, (2) SAME REQUIREMENT IS NECESSARY WHEN STUDYING CORRELATION FOR CONCRETE MIXES PREPARED WITH DIFFERENT KINDS OF CEMENTS, (3) ADDITIVES MAY CHANGE ELASTIC CHARACTERISTICS OF CONCRETES, AND THIS FACT HAS TO BE TAKEN INTO ACCOUNT WHEN STUDYING THE CORRELATION, (4) RESEARCH IS EXTENDED TO FURTHER AGES (3 MONTHS, 6 MONTHS, AND 1 YEAR), (5) TEST RESULTS AT 7 DAYS FOR LEAN MIX CONCRETE SPECIMENS (MOLDED OR CORED FROM PAVEMENTS) ARE WELL REPRESENTED BY THE 7-DAY CURVE FOR CONCRETES, YET GIVING LOWER VALUES OF STRENGTH, AND (6) THIS METHOD IS AN IMPORTANT TOOL FOR LONG RANGE TESTING, AS WELL AS FOR RESEARCH ON DURABILITY. /RRI/

  • Corporate Authors:

    Guanabara Highway Department /Brazil

    ,    
  • Authors:
    • Barbosa, R D
  • Publication Date: 1968

Subject/Index Terms

Filing Info

  • Accession Number: 00213664
  • Record Type: Publication
  • Source Agency: Road Research Institute /Brazil
  • Files: TRIS
  • Created Date: Mar 16 1970 12:00AM